The present invention relates to a ceramic sampler for liquid steel.
Sampling devices or probes for extracting a sample of molten steel from a steel bath are usually constructed as small molds with entrance ducts, openings or the like, and a mold cavity to be filled with steel as the sampler is dipped into the steel bath. The term liquid or molten steel or steel bath is to be understood in a rather wide sense; it is to include, e.g., cast iron melts as well as the content of a blowing steel converter.
Sampling devices of the type referred to above generally, and of known construction, include a cardboard pipe as a holder tube, which containes a two-part mold made of metal and a quartz tube. The mold cavity has the complementary configuration of a disc, i.e., of a flat cylinder. This disc is integral with a pin corresponding to the inlet duct for the mold cavity through which the sampled steel entered the cavity. The disc is usually used for spectrum analysis and the pin for a gas analysis. Hence, the inlet duct is really also part of the mold cavity. This mold is held in the holder tube by a rather easily destructible tube of bound sand and a ceramic front disc. This latter tube has been shifted into a thin wall cardboard tube and bonded thereto. In total, the sampler consists of six distinct parts.
Other sampling devices are known (German Patent No. 2,126,501) which is not quite suited for taking a laboratory type sample, but are used to determine specifically the carbon content of a blowing converter. The geometry of this sampler is not very significant but the device has to carry two temperature sensing elements. This known ceramic sampler has also a two part mold. Just the tooling for making these two different parts is quite expensive. In order to simplify the making of these parts one could divide the mold in longitudinal direction; however, the mold inevitably undergoes a thermal shock when immersed in the steel bath so that dross and slip forms and crystallization water is released which endangers the bondage between the two mold parts because forces act upon them towards separation.